[TRIVIAL PATCH] Kill blk_congestion_wait() stub for !CONFIG_BLOCK

blk_congestion_wait() doesn't exist anymore, but there's still a stub
in blkdev.h for the !CONFIG_BLOCK case.  Kill it.
Signed-off-by: NBenjamin Gilbert <bgilbert@cs.cmu.edu>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

include/linux/blkdev.h

@@ -868,11 +868,6 @@ void kblockd_flush_work(struct work_struct *work);
  */
 #define buffer_heads_over_limit 0
 
-static inline long blk_congestion_wait(int rw, long timeout)
-{
-	return io_schedule_timeout(timeout);
-}
-
 static inline long nr_blockdev_pages(void)
 {
 	return 0;